command 'report' starts nothing and no error occurs in the log

Situation
I am runnning the 'npm run test' on my jenkins server in a Docker Container. Before I builed the refrrences on my local maschine.
The scripts starts with taking and saving the screenshots
Then the command 'report' seems to start but nothing happens. No error and also no compare between the references and the test

Log Output:
CasperJS: Capturing screenshots for computer (1920x1200)
CasperJS: Comparison config file updated.

Bitmap file generation completed.
COMMAND | Executing core for `report`
npm info lifecycle backstopjs@2.0.3~posttest: backstopjs@2.0.3

When i start the same script on my local maschien, everthing works.
I also tried to debug but nothing is logged out either.

My guess is maybe some npm modules or so are missing. But for every execution on the jenkins the node module folders are deleted and then npm install runs.

What kind of modules or software do i need for the 'report' command?